Applications

Explore the working principles, military/civilian applications, and market prospects of tactical-grade fiber optic gyroscopes (FOGs). Learn about top products like GF-3G70 and GF-3G90, and discover their role in aerospace, UAVs, and more. 1. Introduction In the field of modern inertial navigation, Fiber Optic Gyroscopes (FOGs) have become one of the mainstream devices due to their unique advantages. Today, we will delve into the working principles, current market status, and typical product applications of this technology, with a special focus on the performance characteristics of tactical-grade fiber optic gyroscopes. 2. Working Principles of Fiber Optic Gyroscopes A fiber optic gyroscope is an all-solid-state fiber optic sensor based on the Sagnac effect. Its core component is a fiber optic coil, where light emitted by a laser diode propagates in two directions along the coil. When the system rotates, the propagation paths of the two light beams produce a difference. By measuring this optical path difference, the angular displacement of the sensitive component can be precisely determined. Simply put, imagine emitting two beams of light in opposite directions on a circular track. When the track is stationary, the two beams will return to the starting point simultaneously. However, if the track rotates, the light moving against the rotation direction will "travel a longer distance" than the other beam. The fiber optic gyroscope calculates the rotation angle by measuring this minute difference. 3. Technical Classification and Market Status Based on their working methods, fiber optic gyroscopes can be divided into: Interferometric Fiber Optic Gyroscope (I-FOG) Resonant Fiber Optic Gyroscope (R-FOG) Brillouin Scattering Fiber Optic Gyroscope (B-FOG) In terms of accuracy levels, they include: Low-end tactical gradeHigh-end tactical gradeNavigation gradePrecision grade Currently, the fiber optic gyroscope market exhibits dual-use characteristics for military and civilian applications: Military applications: Attitude control for fighter jets/missiles, tank navigation, submarine heading measurement, etc. Civilian applications: Car/aircraft navigation, bridge measurement, oil drilling, etc. It is worth noting that medium-to-high precision fiber optic gyroscopes are primarily used in high-end military equipment such as aerospace, while low-cost, low-precision products are widely applied in civilian fields like oil exploration, agricultural aircraft attitude control, and robotics. 4. Technical Challenges and Development Trends The key to achieving high-precision fiber optic gyroscopes lies in: 1. Studying the impact of optical devices and physical environments on performance. 2. Suppressing relative intensity noise. With the advancement of optoelectronic integration technology and specialty optical fibers, fiber optic gyroscopes are rapidly developing toward miniaturization and cost reduction. Integrated, high-precision, and miniaturized fiber optic gyroscopes will become the mainstream in the future. 5. Recommended Tactical-Grade Fiber Optic Gyroscope Products Taking Micro-Magic Company's products as an example, their tactical-grade fiber optic gyroscopes are characterized by medium precision, low cost, and long lifespan, offering significant price advantages in the market. Below are two popular products: GF-3G70 Performance Characteristics:Bias stability: 0.02~0.05°/h Typical Applications:Electro-optical pods/flight control platformsInertial Navigation Systems (INS)/Inertial Measurement Units (IMU)Platform stabilization devicesPositioning systemsNorth seekers GF-3G90 Performance Characteristics:Higher bias stability: 0.006~0.015°/hLong lifespan, high reliability Typical Applications:UAV flight controlMapping and orbital inertial measurementElectro-optical podsPlatform stabilizers 6. Conclusion Fiber optic gyroscope technology holds significant strategic importance for a country's industrial, defense, and technological development. With technological advancements and the expansion of application scenarios, fiber optic gyroscopes will play a critical role in more fields. Tactical-grade products, with their excellent cost-performance ratio, are gaining widespread application in both military and civilian markets. G-F3G70 Tri-Axis Fiber Optic Gyroscope G-F70ZK Medium and High Precision  Fiber Optic Gyroscope G-F3G90 Tri-Axis Fiber Optic Gyroscope --

Key Points Product: High-Performance Gyroscopes Features: Accurate rotation rate measurement with low bias Compensation for temperature and vibration errors Zero bias stability as a key performance indicator Vibration sensitivity (g-sensitivity and g2-sensitivity) impacts performance Applications: Aerospace, automotive, industrial, and consumer electronics Advantages: High precision with temperature and vibration compensation Improved stability with multiple device averaging Anti-vibration components enhance performance Limitations: Vibration sensitivity is a major error source Zero bias stability may only be achievable in ideal conditions Mechanical impacts can affect performance   Summary: When choosing a gyroscope, it is necessary to consider minimizing the maximum error source. In most applications, vibration sensitivity is the largest source of error. Other parameters can be easily improved by calibration or taking the average of multiple sensors. Zero bias stability is one of the components with a smaller error budget.   When browsing high-performance gyroscope data manuals, the first element that most system designers focus on is the zero bias stability specification. After all, it describes the lower limit of the resolution of the gyroscope and is naturally the best indicator reflecting the performance of the gyroscope! However, actual gyroscopes may experience errors due to various reasons, making it impossible for users to obtain the high zero bias stability claimed in the data manual. Indeed, such high performance may only be achieved in the laboratory. The traditional method is to use compensation to minimize the impact of these error sources to the greatest extent possible. This article will discuss various such technologies and their limitations. Finally, we will discuss another alternative paradigm - selecting gyroscopes based on their mechanical performance and how to improve their bias stability if necessary.   Environmental error All mid to low price MEMS gyroscopes have a certain time zero bias and scaling factor error, and also undergo certain changes with temperature. Therefore, temperature compensation for gyroscopes is a common practice. Generally speaking, the purpose of integrating temperature sensors into gyroscopes is for this purpose. The absolute accuracy of the temperature sensor is not important, what is important is repeatability and the close coupling between the temperature sensor and the actual temperature of the gyroscope. The temperature sensor of modern gyroscopes can almost effortlessly meet these requirements.   Many techniques can be used for temperature compensation, such as polynomial curve fitting, piecewise linear approximation, etc. As long as a sufficient number of temperature points are recorded and sufficient measures are taken during the calibration process, the specific technique used is irrelevant. For example, insufficient storage time at each temperature is a common source of error. However, no matter what technology is used or how careful, temperature hysteresis - the difference in output between cooling and heating to a specific temperature - will be the limiting factor.   The temperature hysteresis loop of gyroscope ADXRS453 is shown in Figure 1. The temperature changes from+25 ° C to+130 ° C, then to -45 ° C, and finally back to+25 ° C, while recording the zero bias measurement results of the uncompensated gyroscope. There is a slight difference in the+25 ° C zero bias output between the heating cycle and the cooling cycle (approximately 0.2 °/s in this example), which is known as temperature hysteresis. This error cannot be eliminated through compensation, as it will occur regardless of whether the gyroscope is powered on or not. In addition, the magnitude of hysteresis is proportional to the amount of temperature "excitation" applied. That is to say, the wider the temperature range applied to the device, the greater the hysteresis. Figure 1. Zero bias output of uncompensated ADXRS453 during temperature cycling (-45 ° C to+130 ° C) If the application allows resetting the zero bias at startup (i.e. starting without rotation), or zeroing the zero bias on site, this error can be ignored. Otherwise, this may be a limiting factor for zero bias stability performance, as we cannot control transportation or storage conditions.   Anti-vibration In an ideal situation, a gyroscope only measures the rotation rate and has nothing else to do with it. However, in practical applications, due to asymmetric mechanical design and/or insufficient precision in microfabrication, all gyroscopes have a certain degree of acceleration sensitivity. In fact, acceleration sensitivity has various external manifestations, and its severity varies depending on the design. The most significant sensitivity is usually the sensitivity to linear acceleration (or g-sensitivity) and the sensitivity to vibration correction (or g2 sensitivity). Due to the fact that most gyroscopes are used in devices that move and/or rotate in a 1g gravity field around the Earth, sensitivity to acceleration is often the largest source of error.   Low cost gyroscopes generally adopt extremely simple and compact mechanical system designs, and their anti vibration performance has not been optimized (it optimizes cost), so vibration may cause serious impacts. It is not surprising that the g sensitivity is above 1000 °/h/g (or 0.3 °/s/g), which is more than 10 times higher than that of high-performance gyroscopes! For this type of gyroscope, the stability of zero bias is of little significance. A slight rotation of the gyroscope in the Earth's gravity field can cause significant errors due to its sensitivity to g and g2. Generally speaking, this type of gyroscope does not specify vibration sensitivity - it defaults to very high.   Some designers attempt to use external accelerometers to compensate for g-sensitivity (usually in IMU applications where the required accelerometer already exists), which can indeed improve performance in certain situations. However, due to various reasons, g sensitivity compensation cannot achieve complete success. The g-sensitivity of most gyroscopes varies with the frequency of vibration. Figure 2 shows the response of Silicon Sensing CRG20-01 gyroscope to vibration. Note that although the sensitivity of the gyroscope is within the rated specification range (slightly exceeding at some specific frequencies, which may not be important), the rate of change from DC to 100 Hz is 12:1, so calibration cannot be simply performed by measuring the sensitivity at DC. Indeed, the compensation plan will be very complex, requiring sensitivity to be changed according to frequency. Figure 2. g-sensitivity response of Silicon Sensing CRG20-01 to different sine tones Another difficulty is to match the phase response of the compensating accelerometer and gyroscope. If the phase response of the gyroscope and compensating accelerometer is not well matched, high-frequency vibration errors may actually be amplified! From this, another conclusion can be drawn: for most gyroscopes, g-sensitivity compensation is only effective at low frequencies. Vibration calibration is often not regulated, possibly due to embarrassing differences or significant differences between different components. It is also possible that it is simply because gyroscope manufacturers are unwilling to test or regulate (to be fair, testing may be difficult). Anyway, vibration correction must be taken into consideration as it cannot be compensated by an accelerometer. Unlike the response of an accelerometer, the output error of a gyroscope will be corrected.   The most common strategy to improve the sensitivity of g2 is to add a mechanical anti vibration component, as shown in Figure 3. The picture shows a Panasonic car gyroscope partially removed from the metal cap shell package. The gyroscope component is isolated from the metal cap by a rubber anti vibration component. Anti vibration components are very difficult to design because their response is not flat over a wide frequency range (especially poor at low frequencies), and their damping characteristics vary with temperature and usage time. Like sensitivity, the vibration correction response of a gyroscope may vary with frequency. Even if anti vibration components can be successfully designed to attenuate narrowband vibrations in a known frequency spectrum, such anti vibration components are not suitable for general applications where wideband vibrations may exist. Figure 3. Typical anti vibration components The main problems caused by mechanical abuse In many applications, routine short-term abuse events may occur, which, although not causing damage to the gyroscope, can result in significant errors. Here are a few examples. Some gyroscopes can withstand rate overload without exhibiting abnormal performance. Figure 4 shows the response of the Silicon Sensing CRG20 gyroscope to rate inputs that exceed the rated range by approximately 70%. The curve on the left shows the response of CRS20 when the rotation rate changes from 0 °/s to 500 °/s and remains constant. The curve on the right shows the response of the device when the input rate decreases from 500 °/s to 0 °/s. When the input rate exceeds the rated measurement range, the output oscillates randomly between tracks. Figure 4. Response of Silicon Sensing CRG-20 to 500 °/s rate input     Some gyroscopes exhibit a tendency to 'lock' even when subjected to impacts of only a few hundred grams. For example, Figure 5 shows the response of VTI SCR1100-D04 to a 250 g 0.5 ms impact (the method of generating the impact is to drop a 5 mm steel ball from a height of 40 cm onto the PCB next to the gyroscope). The gyroscope was not damaged due to impact, but it no longer responds to rate input and needs to be turned off and powered on again to restart. This is not a rare phenomenon, as various gyroscopes exhibit similar behavior. It is wise to check whether the proposed gyroscope can withstand the impact in the application. Figure 5. Response of VTI SCR1100-D04 to 250 g, 0.5 ms impact Obviously, such errors will be astonishingly large. Therefore, it is necessary to carefully identify potential abuse situations in a given application and verify whether the gyroscope can withstand them.   Selecting a new paradigm In error budgeting, zero bias stability is one of the smallest components, so when choosing a gyroscope, a more reasonable approach is to consider minimizing the maximum error source. In most applications, vibration sensitivity is the largest source of error. However, sometimes users may still desire lower noise or better zero bias stability than the selected gyroscope. Fortunately, we have a way to solve this problem, which is to take the average.   Unlike design related environmental or vibration errors, the zero bias stability error of most gyroscopes has noise characteristics. That is to say, the zero bias stability of different devices is not correlated. Therefore, we can improve the zero bias stability performance by taking the average of multiple devices. If n devices are averaged, the expected improvement is √ n. Broadband noise can also be improved by a similar averaging method.   Conclusion For a long time, zero bias stability has been regarded as the absolute standard for gyroscope specifications, but in practical applications, vibration sensitivity is often a more serious factor limiting performance. Choosing a gyroscope based on its anti-vibration capability is reasonable, as other parameters can be easily improved through calibration or averaging multiple sensors.   Appendix: Calculation of Errors Caused by Vibration To calculate the error caused by vibration in a given application, it is necessary to understand the expected amplitude of acceleration and the frequency at which this acceleration may occur. l  Running typically produces a peak of 2 grams, accounting for approximately 4% of the time. l  The vibration of the helicopter is quite stable. Most helicopter specifications are 0.4 g wideband vibration and 100% duty cycle. l  Ships (especially small boats) on turbulent waters can tilt up to ± 30 ° (producing ± 0.5 g of vibration). The duty cycle can be assumed to be 20%. l  For construction equipment such as leveling machines and front-end loaders, as long as their blades or buckets hit stones, they will produce a high g (50 g) and brief impact. The typical duty cycle value is 1%.   When calculating the error caused by vibration, it is necessary to consider the sensitivity of g and g2. Taking helicopter application as an example, the calculation is as follows: Error=[g sensitivity error]+[g2 sensitivity error] =[0.4 g x g sensitivity x 3600 s/h x 100%]+ [(0.4 g) 2 × g2 sensitivity × 3600 s/h × 100%] If the sensitivity of g is compensated by an accelerometer, only the sensitivity of g decreases, and the decrease is the compensation coefficient.   MG502 MG-502 HIGH PRECISION MEMS SINGLE AXIS GYROSCOPES   --

Key Points Product: Fiber Optic Gyroscopes (FOGs) Features: • Highly accurate sensor for measuring angular velocity • Low bias stability (≤0.2 °/h), ensuring high measurement accuracy • Low random walk (ARW) for stable output over time (e.g., 0.001°/√h) • Scale factor accuracy (e.g., 10 ppm) with minimal deviation from actual rotation • Sensitive to temperature, vibration, and light source changes Applications: • Aviation: Provides accurate position, velocity, and attitude data for aircraft • Navigation: Assists in guidance and positioning systems • Seismic Research: Monitors rotational movement during earthquake studies • Military: Used in missile and bomb guidance systems Advantages: • High precision and stability • Low power consumption, easy installation and maintenance • Reliable in dynamic environments with minimal drift and noise • Versatile in various applications requiring precision angular velocity measurement     Fiber optic gyroscopes (FOGs) are highly accurate sensors used to measure angular velocity. They are widely used in fields such as aviation, navigation, and seismic research due to their high precision, sensitivity, and excellent stability. Its core accuracy indicators, including zero bias drift, random walk, and angle measurement error, are the key to evaluating its performance. Detailed explanation of core accuracy indicators Fiber optic gyroscope uses optical fibers as sensing elements to achieve accurate measurement of rotational angular velocity. Its accuracy performance can be comprehensively evaluated through the following three indicators:   (1)    Bias Stability (Drift Rate)   This indicator reflects the output accuracy of the gyroscope in a non rotating state, usually measured by a benchmark accuracy. The zero bias drift of fiber optic gyroscope is extremely low, generally not exceeding 0.2 °/h, ensuring high measurement accuracy.   (2)    Random Walk (Angular Random Walk, ARW)   This indicator measures the stability of the gyroscope output value over a period of time. typically measured in degrees per square root hour (°/√h). For example, the FOG has an ARW of 0.001°/√h. This means that the noise in the gyroscope's output accumulates at a rate of 0.001 degrees per square root of the operating time. (3)     Scale Factor Accuracy   The scale factor accuracy indicates how well the gyroscope's output corresponds to the actual angular velocity. It is usually expressed as a percentage error. For example, The FOG has a scale factor accuracy of 10 ppm (parts per million)**. This means that for every degree per second (°/s) of actual rotation, the gyroscope's output may deviate by up to 0.001%.   Analysis of Factors Affecting Accuracy The accuracy of fiber optic gyroscopes is influenced by various external factors: (1)    Temperature: The sensitive components of fiber optic gyroscopes are sensitive to changes in ambient temperature, which may lead to zero bias drift or increased angle measurement errors. (2)    Vibration: Environmental vibrations can have adverse effects on the accuracy of fiber optic gyroscopes, potentially leading to unstable output values. (3)   Light source: Changes in parameters such as power and wavelength of the light source may also affect the output value of the fiber optic gyroscope, thereby affecting its accuracy. Example of G-F3G70 manufactured by Micro-Magic the G-F3G70 fiber optic gyroscope inertial group is designed for medium and high precision application backgrounds. It adopts three-axis common technology and split design, with low cost and stable performance. The structure adopts optical path and circuit integrated packaging, with simple structure and easy installation. It can be used in navigation guidance, attitude measurement and control systems of small missiles and guided bombs. Main performance index of the fiber-optic gyroscope   G-F3G70-A G-F3G70-B G-F3G70-C Unit zero bias stability ≤0.050 (10s) ≤0.03 (10s ) ≤0.02 (10s) (°)/h Zero bias stability full temperature (1℃/min, 100s ) ≤0.15 ≤0.12 ≤0.10 (°)/h Zero bias repeatability ≤0.050 ≤0.03 ≤0.03 (°)/h Random walk coefficient ≤0.002 ≤0.002 ≤0.001 (º)/h1/2 Scale factor nonlinearity ≤20 ppm Scale factor asymmetry ≤20 ppm Scale factor repeatability ≤20 ppm Conclusion With its high precision advantage, fiber optic gyroscopes have been widely used in fields such as aviation, navigation, and earthquake research. For example, in aircraft, fiber optic gyroscopes can accurately determine the position, velocity, and attitude of the aircraft, ensuring stable and precise flight direction. In summary, as a high-precision measurement device, the performance of fiber optic gyroscope is affected by various factors, but it still shows great potential and value in various fields of application.       G-F3G70 Affordable price Dynamic Range 400 Deg/S Optic Fiber Gyroscopes China Leading Supplier    

Explore comprehensive testing methods for fiber optic gyroscope key indicators, including zero bias stability, scale factor nonlinearity, and random walk coefficient (RWC). Learn step-by-step procedures, formulas, and equipment requirements for precision navigation and attitude control applications. Fiber optic gyroscope is based on Sagna effect and is widely used for measuring angular velocity in navigation and attitude control. Key indicators typically include zero bias stability, scaling factor, random walk, bandwidth, noise, temperature characteristics, and so on. By measuring these indicators, the performance of fiber optic gyroscopes can be comprehensively evaluated, and system design and compensation algorithms can be optimized based on these data.   1. Zero Bias Series Testing 1.1 Bias Definition： The average equivalent angular velocity output of a fiber optic gyroscope when there is no angular velocity input. Test Equipment: horizontal reference device, fiber optic gyroscope output measurement recording device. Test method: Fix the fiber optic gyroscope on a horizontal reference, with the input axis (IRA) pointing in the east-west direction. Record output data for at least 1 hour after power on, with a sampling frequency that meets the Nyquist criterion (≥ 2 times the highest frequency of the signal). Calculation formula:                 Where K is the scaling factor, is the average output value.   1.2 Bias Stability Definition: The degree of dispersion of zero bias output around the mean reflects short-term stability. Test method: Same as bias test, but requires long-term data recording (at least 1 hour). Calculation formula:                   where:  ： Zero bias stability, measured in degrees per hour (° ⁄ h) :  The single-sided amplitude output of the fiber optic gyroscope  at time .   1.3 Bias Repeatability Definition: Perform multiple power tests to ensure consistency of zero bias. Test method: Repeat the zero-bias test for more than 6 times, with power off and cooling to room temperature at intervals between each test. Calculation formula: For each test data, process it according to formula (1), calculate the zero bias, and then calculate the zero-bias repeatability of Q tests according to the following formula.                        Where,   :  Zero bias of the i-th test; :  Zero bias   1.4 Bias Temperature Sensitivity Definition: Zero bias drift caused by temperature changes. Test method: Set different temperature points (covering the working temperature range) inside the temperature control box, and maintain a constant temperature for 30 minutes at each temperature point. Measure the zero bias at each temperature point and calculate the deviation from the room temperature zero bias. Calculation formula: The test data is processed according to formula (1), and the zero bias of the fiber optic gyroscope at room temperature and each test temperature point is calculated separately. The zero bias temperature sensitivity of the fiber optic gyroscope is calculated according to the following formula:                             ：The i-th test temperature.  ：room temperature   2. Scale Factor Series Testing 2.1  Scale Factor Definition: Linear proportional relationship between output signal and input angular velocity Test equipment: high-precision rate turntable (error<1/3 of the tested gyroscope index) Test method: Select ≥ 11 angular velocity points (including the maximum input angular velocity) uniformly in both forward and reverse directions. Record the mean output of each point and fit a straight line using the least squares method. Calculation formula: Let be the average output of the fiber optic gyroscope at the jth input angular velocity, and the scaling factor calculation method is as follows:                                               The linear model for establishing the input-output relationship of fiber optic gyroscope is as follows:                     Using the least squares method to calculate K,                               Where ∅ is the rotational speed of the speed turntable, measured in degrees per second (° ⁄ s)   2.2 Scale factor nonlinearity Definition: Output the maximum deviation relative to the fitted line. Calculation formula: According to the above method, the input-output relationship of the fiber optic gyroscope is represented by fitting a straight line as follows:               Calculate the point-by-point nonlinear deviation of the output characteristics of the fiber optic gyroscope according to the following formula:                   Calculate the scaling factor linearity according to the following formula, and create the nonlinear deviation curve of the fiber optic gyroscope output (the horizontal axis represents the input angular velocity, and the vertical axis represents the nonlinear deviation)                   2.3 Scale factor temperature sensitivity Test method: Test the scaling factor at different temperature points and calculate the deviation caused by temperature changes. Calculation formula: The test data is processed according to the calculation method of scale factor, and the scale factor of the fiber optic gyroscope at room temperature and each test temperature point is calculated separately. The temperature sensitivity of the scale factor is calculated according to the following formula:                 3. Random Walk Coefficient (RWC) Definition: Integral angular velocity error caused by white noise output. Test method: Short time (tens of seconds) high-frequency sampling, analyze Allan variance. Formula for calculating Allan variance: a) There are n initial sample data of fiber optic gyroscope output values obtained at the initial sampling interval time . According to the calculation formula for gyroscope zero bias, the output angular velocity of each fiber optic gyroscope output value is calculated to obtain the initial sample data of output angular velocity, as shown in the following formula:               b) For continuous data of n initial samples, k continuous data are grouped together, and the time length of the array is set to , where τ equals , 2 ,  Calculate the average value of the array data for each time length. c) Find the average difference between two adjacent arrays:           d) Calculate the variance of a set of random variables:   …… (17) Repeat the above process with different values of, and obtain a curve in the double logarithmic coordinate system, which is called the Allan variance curve. Using the Allan variance model below, the coefficients are obtained through least squares fitting, and then the random walk coefficient RWC is calculated:                   Conclusion: The key indicator testing of fiber optic gyroscope is a bridge connecting research and development with practical applications. By quantitatively verifying performance, ensuring reliability, and meeting standard compliance, it ensures its "precision, stability, and usability" in military and civilian high-precision fields, while laying the foundation for technological innovation and cost optimization. GF2X64 Dual-Axis Low Precision Fiber Optic Gyroscope GF-60 Medium and Low Precision  Fiber Optic Gyroscope GF3G90 Tri-Axis Fiber Optic Gyroscope    

Key Points Product: Fiber Optic Gyroscope (FOG) Key Features: Components: Solid-state sensor using optical fiber for precise inertial measurements. Function: Leverages the SAGNAC effect for accurate angular rate sensing without moving parts. Applications: Suitable for IMUs, INS, missile seekers, UAVs, and robotics. Data Fusion: Combines FOG data with external references to enhance accuracy and stability. Conclusion: FOGs provide high precision and reliability in navigation tasks, with promising future developments across various sectors. Like ring laser gyro, fiber optic gyro has the advantages of no mechanical moving parts, no preheating time, insensitive acceleration, wide dynamic range, digital output and small size. In addition, fiber optic gyro also overcomes the fatal shortcomings of ring laser gyro such as high cost and blocking phenomenon. Fiber optic gyro is a kind of optical fiber sensor used in inertial navigation.Because it has no moving parts – high-speed rotor, called solid state gyroscope. This new all-solid gyroscope will become the leading product in the future and has a wide range of development prospects and application prospects. 1. Fiber optic gyro classification According to the working principle, fiber optic gyroscope can be divided into interferometric fiber optic gyro (I-FOG), resonant fiber optic gyro (R-FOG) and stimulated Brillouin scattering fiber optic gyroscope (B-FOG). At present, the most mature fiber optic gyro is the interferometric fiber optic gyroscope (that is, the first generation of fiber optic gyroscope), which is the most widely used. It uses multi-turn optical fiber coil to enhance SAGNAC effect. A double-beam ring interferometer composed of multi-turn single-mode optical fiber coil can provide high accuracy, but also will inevitably make the overall structure more complicated.Fiber optic gyros are divided into open ring fiber optic gyroscopes and closed loop fiber optic gyros according to the type of loop. Open-loop fiber optic gyro without feedback, directly detect the optical output, save many complex optical and circuit structure, has the advantages of simple structure, cheap price, high reliability, low power consumption, the disadvantage is the input-output linearity is poor, small dynamic range, mainly used as an Angle sensor. The basic structure of an open-loop interferometric fiber optic gyro is a ring dual-beam interferometer. It is mainly used for occasions where the accuracy is not high and the volume is small. 2. Status and future of fiber optic gyroscope With the rapid development of fiber optic gyro, many large companies, especially military equipment companies, have invested huge financial resources to study it. The main research companies for the United States, Japan, Germany, France, Italy, Russia, low and medium precision gyroscope has completed the industrialization, and the United States has maintained a leading position in this area of research.The development of fiber optic gyroscope is still at a relatively backward level in our country. According to the level of development, the gyro development is divided into three echelons: the first echelon is the United States, the United Kingdom, France, they have all the gyro and inertial navigation research and development capabilities; The second tier is mainly Japan, Germany, Russia; China is currently in the third tier. The research of fiber optic gyro in China started relatively late, but with the efforts of the majority of scientific researchers, it has gradually narrowed the gap between us and the developed countries.At present, China’s fiber optic gyro industry chain is complete, and manufacturers can be found upstream and downstream of the industry chain, and the development accuracy of fiber optic gyro has reached the requirements of middle and low accuracy of inertial navigation system. Although the performance is relatively poor, it will not bottleneck like the chip.The future development of fiber optic gyro will focus on the following aspects:(1) High precision. Higher precision is an inevitable requirement for fiber optic gyro to replace laser gyro in advanced navigation. At present, the high precision fiber optic gyro technology is not fully mature.(2) High stability and anti-interference. Long-term high stability is also one of the development directions of fiber optic gyroscope, which can maintain navigation accuracy for a long time under harsh environment is the requirement of inertial navigation system for gyroscope. For example, in the case of high temperature, strong earthquake, strong magnetic field, etc., the fiber optic gyro must also have sufficient accuracy to meet the requirements of users.(3) Product diversification. It is necessary to develop products with different precision and different needs. Different users have different requirements for navigation accuracy, and the structure of the fiber optic gyro is simple, and only the length and diameter of the coil need to be adjusted when changing the accuracy. In this respect, it has the advantage of surpassing mechanical gyro and laser gyro, and its different precision products are easier to achieve, which is the inevitable requirement of the practical application of fiber optic gyro.(4) Production scale. The reduction of cost is also one of the preconditions for fiber optic gyro to be accepted by users. The production scale of various components can effectively promote the reduction of production costs, especially for middle and low precision fiber optic gyro. 3.Summary The zero bias stability of the fiber optic gyroscope F50 is 0.1~0.3º/h, and the zero bias stability of the F60 is 0.05~0.2º/h. Their application fields are basically the same, and can be used in small IMU, INS, missile seeker servo tracking, photoelectric pod, UAV and other application fields. If you want more technical data, please feel free to contact us. GF50 Single-Axis Medium Accuracy Military Standard Fiber Optic Gyroscope   GF60 Single Axis Fiber Gyro Low Power Fiber Optic Gyro Imu Angular Rate for Navigation  

Key Points Product: Pure Inertial Navigation System (INS) Based on IMU Key Features: Components: Uses MEMS accelerometers and gyroscopes for real-time measurement of acceleration and angular velocity. Function: Integrates initial position and attitude data with IMU measurements to calculate real-time position and attitude. Applications: Ideal for indoor navigation, aerospace, autonomous systems, and robotics. Challenges: Addresses sensor errors, cumulative drift, and dynamic environment impacts with calibration and filtering methods. Conclusion: Provides precise positioning in challenging environments, with robust performance when combined with auxiliary positioning systems like GPS.   The law of instrument constant drift with temperature of a gyro theodolite is a complex phenomenon, which involves the interaction of multiple components and systems within the instrument. Instrument constant refers to the measurement reference value of the gyro-theodolite under specific conditions. It is crucial to ensure measurement accuracy and stability. Temperature changes will cause the drift of instrument constants, mainly because the differences in thermal expansion coefficients of materials cause changes in the instrument structure, and the performance of electronic components changes with temperature changes. This drift pattern is often nonlinear because different materials and components respond differently to temperature. In order to study the drift of the instrument constants of a gyro theodolite with temperature, a series of experiments and data analysis are usually required. This includes calibrating and measuring the instrument at different temperatures, recording changes in instrument constants, and analyzing the relationship between temperature and instrument constants. Through the analysis of experimental data, the trend of instrument constants changing with temperature can be found, and an attempt can be made to establish a mathematical model to describe this relationship. Such models can be based on linear regression, polynomial fitting, or other statistical methods and are used to predict and compensate for drift in instrument constants at different temperatures. Understanding the drift of the instrument constants of a gyro theodolite with temperature is very important to improve measurement accuracy and stability. By taking corresponding compensation measures, such as temperature control, calibration and data processing, the impact of temperature on instrument constants can be reduced, thereby improving the measurement performance of the gyro theodolite. It should be noted that the specific drift rules and compensation methods may vary depending on different gyro theodolite models and application scenarios. Therefore, in practical applications, corresponding measures need to be studied and implemented according to specific situations. The study of the drift pattern of instrument constants of gyro theodolite with temperature usually involves monitoring and analyzing the performance of the instrument under different temperature conditions. The purpose of such research is to understand how changes in temperature affect the instrument constants of a gyro theodolite and possibly find a way to compensate or correct for this temperature effect. Instrumental constants generally refer to the inherent properties of an instrument under specific conditions, such as standard temperature. For gyro theodolite, instrument constants may be related to its measurement accuracy, stability, etc. When the ambient temperature changes, the material properties, mechanical structure, etc. inside the instrument may change, thus affecting the instrument constants. To study this drift pattern, the following steps are usually required: Select a range of different temperature points to cover the operating environments a gyroscopic theodolite may encounter.Take multiple directional measurements at each temperature point to obtain sufficient data samples.Analyze the data and observe the trend of instrument constants as a function of temperature.Try to build a mathematical model to describe this relationship, such as linear regression, polynomial fitting, etc.Use this model to predict instrument constants at different temperatures and possibly develop methods to compensate for temperature effects. A mathematical model might look like this: K(T) = a + b × T + c × T^2 + … Among them, K(T) is the instrument constant at temperature T, and a, b, c, etc. are the coefficients to be fitted. This kind of research is of great significance for improving the performance of gyro theodolite under different environmental conditions. It should be noted that specific research methods and mathematical models may vary depending on specific instrument models and application scenarios. Summarize The law of instrument constant drift with temperature of a gyro theodolite is a complex phenomenon, which involves the interaction of multiple components and systems within the instrument. Instrument constant refers to the measurement reference value of the gyro-theodolite under specific conditions. It is crucial to ensure measurement accuracy and stability. Temperature changes will cause the drift of instrument constants, mainly because the differences in thermal expansion coefficients of materials cause changes in the instrument structure, and the performance of electronic components changes with temperature changes. This drift pattern is often nonlinear because different materials and components respond differently to temperature. In order to study the drift of the instrument constants of a gyro theodolite with temperature, a series of experiments and data analysis are usually required. This includes calibrating and measuring the instrument at different temperatures, recording changes in instrument constants, and analyzing the relationship between temperature and instrument constants. Through the analysis of experimental data, the trend of instrument constants changing with temperature can be found, and an attempt can be made to establish a mathematical model to describe this relationship. Such models can be based on linear regression, polynomial fitting, or other statistical methods and are used to predict and compensate for drift in instrument constants at different temperatures. Understanding the drift of the instrument constants of a gyro theodolite with temperature is very important to improve measurement accuracy and stability. By taking corresponding compensation measures, such as temperature control, calibration and data processing, the impact of temperature on instrument constants can be reduced, thereby improving the measurement performance of the gyro theodolite. It should be noted that the specific drift rules and compensation methods may vary depending on different gyro theodolite models and application scenarios. Therefore, in practical applications, corresponding measures need to be studied and implemented according to specific situations. The study of the drift pattern of instrument constants of gyro theodolite with temperature usually involves monitoring and analyzing the performance of the instrument under different temperature conditions. The purpose of such research is to understand how changes in temperature affect the instrument constants of a gyro theodolite and possibly find a way to compensate or correct for this temperature effect. Instrumental constants generally refer to the inherent properties of an instrument under specific conditions, such as standard temperature. For gyro theodolite, instrument constants may be related to its measurement accuracy, stability, etc. When the ambient temperature changes, the material properties, mechanical structure, etc. inside the instrument may change, thus affecting the instrument constants. To study this drift pattern, the following steps are usually required: Select a range of different temperature points to cover the operating environments a gyroscopic theodolite may encounter.Take multiple directional measurements at each temperature point to obtain sufficient data samples.Analyze the data and observe the trend of instrument constants as a function of temperature.Try to build a mathematical model to describe this relationship, such as linear regression, polynomial fitting, etc.Use this model to predict instrument constants at different temperatures and possibly develop methods to compensate for temperature effects. A mathematical model might look like this: K(T) = a + b × T + c × T^2 + … Among them, K(T) is the instrument constant at temperature T, and a, b, c, etc. are the coefficients to be fitted. This kind of research is of great significance for improving the performance of gyro theodolite under different environmental conditions. It should be noted that specific research methods and mathematical models may vary depending on specific instrument models and application scenarios.   MG502 MEMS Gyroscope MG502    

Key Points Product: MEMS Gyroscope Borehole North Finding System Key Features: Components: Employs MEMS gyroscopes for north-seeking, featuring compact size, low cost, and high shock resistance. Function: Uses an improved two-position method (90° and 270°) and real-time attitude correction for precise north determination. Applications: Optimized for downhole drilling systems in complex underground environments. Data Fusion: Combines gyroscope data with local magnetic declination corrections for true north calculation, ensuring accurate navigation during drilling. Conclusion: Delivers precise, reliable, and independent north-finding capabilities, ideal for borehole and similar applications. The new MEMS gyroscope is a kind of inertial gyro with simple structure, which has the advantages of low cost, small size and resistance to high shock vibration. The inertial north seeking gyroscope can complete the independent north seeking all weather without external restrictions, and can achieve fast, high efficiency, high precision and continuous work. Based on the advantages of MEMS gyro, MEMS gyro is very suitable for downhole north finding system. This paper describes the segmented fusion research of MEMS gyro borehole north finding system. The following will introduce the improved two-position north finding, the scheme of MEMS gyro borehole fusion north finding and the determination of north finding value. Improved two-position north finding The static two-position north seeking scheme generally selects 0° and 180° as the initial and end positions of north seeking. After repeated experiments, the gyro output angular velocity is collected, and the final north seeking Angle is obtained by combining the local latitude. The experiment adopted the two-position method every 10°, collected 360° of the turntable, and a total of 36 sets of data were collected. After averaging each set of data, the measured solution values were shown in Figure 1 below. Figure 1 Fitting curve of gyroscope output from 0 to 360° As can be seen from Figure 1, the output fitting curve is a cosine curve, but the experimental data and angles are still small, and the experimental results lack accuracy. Repeated experiments were conducted, and the Angle of acquisition was extended to 0~660°, and the two-position method was conducted every 10° from 0°, and the data results were shown in Figure 2. The trend of the image is cosine curve, and there are obvious differences in data distribution. At the crest and trough of the cosine curve, the distribution of data points is scattered and the degree of fit to the curve is low, while at the place with the highest slope of the curve, the fit of data points to the curve is more obvious. Figure 2 Fitting curve of gyroscope output at two positions 0~660° Combined with the relationship between azimuth and gyro output amplitude in Figure 3, it can be concluded that the data fit is better when the two-position north finding is adopted at 90° and 270°, indicating that it is easier and more accurate to detect the north Angle in the east-west direction. Therefore, 90°, 270°, instead of 0° and 180°, are used in this paper as the two-position north seeking gyro output acquisition positions. Figure 3 Relation between azimuth and gyro output amplitude MEMS gyroscope borehole fusion northfinding When MEMS gyro is used in borehole north finding system, it is faced with complex environment, and there will be variable attitude Angle with drill bit drilling, so the solution of north Angle becomes much more complicated. In this section, based on the improvement of the two-position north finding scheme in the previous section, a method is proposed to obtain the attitude Angle by controlling rotation according to the output data information, and the included Angle with the north is obtained. The specific flow chart is shown in Figure 4. The MEMS gyroscope is transmitted to the upper computer through RS232 data interface. As shown in Figure 4, after the initial north Angle is obtained by searching north at the two positions, the next step of drilling while drilling is carried out. After receiving the north seeking instruction, the drilling work stops. The attitude Angle output by MEMS gyro is collected and transmitted to the upper computer. The rotation of the borehole north seeking system is controlled by the attitude Angle information, and the roll Angle and pitch Angle are adjusted to 0. The heading Angle at this moment is the Angle between the sensitive axis and the magnetic north direction. In this scheme, the Angle between MEMS gyroscope and true north direction can be obtained in real time by collecting attitude Angle information. Figure 4 Fusion north finding flow chart The north seeking value is determined In the fusion north finding scheme, the improved two-position north finding was performed on the MEMS gyroscope. After the north finding was completed, the initial north position was obtained, the heading Angle θ was recorded, and the initial attitude state was (0,0,θ), as shown in Figure 5(a). When the bit is drilling, the attitude Angle of the gyroscope changes, and the roll Angle and pitch Angle are regulated by the rotary table, as shown in Figure 5(b). As shown in Figure 5(b), when drilling the bit, the system receives the attitude Angle information of the attitude instrument, and needs to judge the sizes of roll Angle γ ‘and pitch Angle β’, and rotate them through the rotation control system to make them turn to 0. At this time, the output heading Angle data is the Angle between the sensitive axis and the magnetic north direction. The Angle between the sensitive axis and the true north direction should be obtained according to the relationship between the magnetic north and the true north direction, and the true north Angle should be obtained by combining the local magnetic declination Angle. The solution is as follows: θ’=Φ-∆φ In the above formula, θ ‘drill bit and the true north direction Angle, ∆φ is the local magnetic declination Angle, Φ is the drill bit and magnetic north Angle. Figure 5 Change of initial and drilling attitude Angle The north seeking value is determined In this chapter, the north finding scheme of MEMS gyroscope underground north finding system is studied. Based on the two-position north finding scheme, an improved two-position north finding scheme with 90° and 270° as starting positions is proposed. With the continuous progress of MEMS gyroscope, MEMS north-seeking gyroscope can achieve independent north finding, such as MG2-101, its dynamic measurement range is 100°/s, can work in the environment of -40 ° C ~+85 ° C, its bias instability is 0.1°/hr, and the angular velocity random walk is 0.005°/√hr. I hope you can understand the north finding scheme of MEMS gyroscope through this article, and look forward to discussing professional issues with you.   MG502 MEMS Gyroscope MG502    

Key Points Product: Integrated Optical Chip-Based Fiber Optic Gyroscope Key Features: Components: Uses an integrated optical chip combining functions like luminescence, beam splitting, modulation, and detection on a lithium niobate thin film (LNOI) platform. Function: Achieves “multi-in-one” integration of non-sensitive optical path functions, reducing size and production costs while enhancing polarization and phase modulation for accurate gyroscope performance. Applications: Suited for positioning, navigation, attitude control, and oil well inclination measurement. Optimization: Further improvements in polarization extinction ratio, emission power, and coupling efficiency can enhance stability and accuracy. Conclusion: This integrated design paves the way for miniaturized, low-cost fiber optic gyroscopes, meeting the growing demand for compact and reliable inertial navigation solutions. With the advantages of all-solid state, high performance and flexible design, fiber optic gyroscope has become the mainstream inertial gyroscope, which is widely used in many fields such as positioning and navigation, attitude control and oil well inclination measurement. Under the new situation, the new generation of inertial navigation system is developing towards miniaturization and low cost, which puts forward higher and higher requirements for the comprehensive performance of gyroscope such as volume, accuracy and cost. In recent years, hemispherical resonator gyro and MEMS gyro have developed rapidly with the advantage of small size, which has a certain impact on the fiber optic gyro market. The main challenge of traditional optical gyro volume reduction is the reduction of optical path volume. In the traditional scheme, the optical route of fiber optic gyro is composed of several discrete optical devices, each of which is realized based on different principles and processes and has independent packaging and pigtail. As a result, the device volume under the prior art is close to the reduction limit, and it is difficult to support the further reduction of the volume of fiber optic gyro. Therefore, it is urgent to explore new technical solutions to realize the effective integration of different functions of the optical path, greatly reduce the volume of the gyro optical path, improve the process compatibility, and reduce the production cost of the device. With the development of semiconductor integrated circuit technology, integrated optical technology has gradually achieved breakthroughs, and the feature size has been continuously reduced, and it has entered the micro and nano level, which has greatly promoted the technical development of integrated optical chips, and has been applied in optical communication, optical computing, optical sensing and other fields. The integrated optical technology provides a new and promising technical solution for the miniaturization and low cost of fiber optic gyro optical path. 1 Integrated optical chip scheme design 1.1 Overall Design The traditional optical routing light source (SLD or ASE), fiber taper coupler (referred to as “coupler”), Y branch waveguide phase modulator (referred to as “Y waveguide modulator”), detector, sensitive ring (fiber ring). Among them, the sensitive ring is the core unit of the sensitive Angle rate, and its volume size directly affects the precision of the gyro.We propose a hybrid integrated chip, which consists of a light source component, a multifunctional component and a detection component through hybrid integration. Among them, the light source part is an independent component, which is composed of SLD chip, isolation collimation component and peripheral components such as heat sink and semiconductor cooler. The detection module consists of a detection chip and a transresistance amplifier chip. The multifunctional module is the main body of hybrid integrated chip, which is realized based on lithium niobate thin film (LNOI) chip, and mainly includes optical waveguide, mode-spot conversion, polarizer, beam splitter, mode attenuator, modulator and other on-chip structures. The beam emitted by the SLD chip is transmitted into the LNOI waveguide after isolation and collimation.The polarizer deflects the input light, and the mode attenuator attenuates the non-working mode. After the beam splitter splits the beam and modulator modulates the phase, the output chip enters the sensitive ring and the sensitive angular rate. The light intensity is captured by the detector chip, and the generated photoelectric output flows through the transresistance amplifier chip to the demodulation circuit.The hybrid integrated optical chip has the functions of luminescence, beam splitting, beam combining, deflection, modulation, detection, etc. It realizes the “multi-in-one” integration of non-sensitive functions of gyro optical path. Fiber optic gyroscopes depend on the sensitive Angle rate of coherent beam with high degree of polarization, and the polarization performance directly affects the precision of gyroscopes. The traditional Y-waveguide modulator itself is an integrated device, which has the functions of deflection, beam splitting, beam combining and modulation. Thanks to material modification methods such as proton exchange or titanium diffusion, Y-waveguide modulators have extremely high deflection ability. However, thin film materials need to take into account the requirements of size, integration and deflection ability, which can not be met by material modification methods. On the other hand, the mode field of thin film optical waveguide is much smaller than that of bulk material optical waveguide, resulting in changes in electrostatic field distribution and electrorefractive index parameters, and the electrode structure needs to be redesigned. Therefore, the polarizer and modulator are the core design points of the “all-in-one” chip. 1.2 Specific Design The polarization characteristics are obtained by structural bias, and an on-chip polarizer is designed, which consists of curved waveguide and straight waveguideAgreed. The curved waveguide can limit the difference between the transmission mode and the non-transmission mode, and achieve the effect of mode bias. The transmission loss of the transmission mode is reduced by setting the offset.The transmission characteristics of optical waveguide are mainly affected by scattering loss, mode leakage, radiation loss and mode mismatch loss. Theoretically, the scattering loss and mode leakage of small curved waveguides are small, which are mainly limited by the late process. However, the radiation loss of curved waveguides is inherent and has different effects on different modes. The transmission characteristics of the curved waveguide are mainly affected by the mode mismatch loss, and there is mode overlap at the junction of the straight waveguide and the curved waveguide, resulting in a sharp increase in mode scattering. When the light wave is transmitted into the polarized waveguide, due to the existence of curvature, the effective refractive index of the light wave mode is different in the vertical direction and the parallel direction, and the mode restriction is different, which results in different attenuation effects for TE and TM modes.Therefore, it is necessary to design the bending waveguide parameters to achieve the deflection performance. Among them, bending radius is the key parameter of bending waveguide. The transmission loss under different bending radius and the loss comparison between different modes are calculated by FDTD eigenmode solver. The calculated results show that the loss of the waveguide decreases with the increase of the radius at small bending radius. On this basis, the relationship between polarization property (ratio of TE mode to TM mode) and bending radius is calculated, and the polarization property is inversely proportional to bending radius. The determination of the bending radius of the on-chip polarizer should consider the theoretical calculation, the simulation results, the technological capability and the actual demand.The finite difference Time domain (FDTD) is used to simulate the transmitted light field of the on-chip polarizer. The TE mode can pass through the waveguide structure with low loss, while the TM mode can produce obvious mode attenuation, so as to obtain polarized light with high extinction ratio. By increasing the number of cascaded waveguides, the extinction ratio of the polarization-extinction ratio can be further improved, and better than -35dB polarization extinction ratio performance can be obtained on the micron scale. At the same time, the structure of the waveguide on chip is simple, and it is easy to realize the low-cost fabrication of the device. 2 Integrated optical chip performance verification The LNOI main chip of the integrated optical chip is an unsliced sample engraved with multiple chip structures, and the size of a single LNOI main chip is 11mm×3mm. The performance test of integrated optical chip mainly includes the measurement of spectral ratio, polarization extinction ratio and half-wave voltage.Based on the integrated optical chip, a gyroscope prototype is built, and the performance test of the integrated optical chip is carried out. Static zero bias performance of a gyro prototype based on integrated optical chip in a non-vibration isolated foundation at room temperature. set-basedThe gyroscope formed into optical chip has a long time drift in the start-up segment, which is mainly caused by the start-up characteristic of light source and the large loss of optical link. In the 90min test, the zero bias stability of the gyroscope is 0.17°/h (10s). Compared with the gyroscope based on traditional discrete devices, the zero bias stability index deteriorates by an order of magnitude, indicating that the integrated optical chip needs to be further optimized. Main optimization directions: improve the polarization extinction ratio of the chip, improve the luminous power of the light-emitting chip, improve the end-coupling efficiency of the chip, and reduce the overall loss of the integrated chip. 3 Summary We propose an integrated optical chip based on LNOI, which can realize the integration of non-sensitive functions such as luminescence, beam splitting, beam combining, deflection, modulation and detection. The zero bias stability of the gyro prototype based on the integrated optical chip is 0.17°/h. Compared with the traditional discrete devices, the performance of the chip still has a certain gap, which needs to be further optimized and improved. We preliminarily explore the feasibility of fully integrated optical path functions except ring, which can maximize the application value of integrated optical chip in gyro, and meet the development needs of miniaturization and low cost of fiber optic gyro. GF50 Single-Axis Medium Accuracy Military Standard Fiber Optic Gyroscope   GF60 Single Axis Fiber Gyro Low Power Fiber Optic Gyro Imu Angular Rate for Navigation  

Key Points Product: Fiber Optic Gyroscope-Based Deformation Detection System Key Features: Components: Incorporates high-precision fiber optic gyroscopes for angular velocity measurement and trajectory calculation. Function: Combines gyroscopic data with distance measurements to detect structural deformations with high accuracy. Applications: Suitable for civil engineering, structural health monitoring, and deformation analysis in bridges, buildings, and other infrastructures. Performance: Achieves deformation detection accuracy better than 10 μm at a running speed of 2 m/s using medium-precision gyroscopes. Advantages: Compact design, lightweight, low power consumption, and user-friendly operation for ease of deployment. Conclusion:This system provides precise and reliable deformation measurements, offering valuable solutions for engineering and structural analysis needs. 1 Method of engineering structure deformation detection based on fiber optic gyroscope The principle of the engineering structure deformation detection method based on fiber optic gyro is to fix the fiber optic gyro to the detection device, measure the angular velocity of the detection system when running on the measured surface of the engineering structure, measure the operating distance of the detection device, and calculate the operating trajectory of the detection device to realize the detection of engineering structure deformation. This method is referred to as the trajectory method in this paper. This method can be described as “two-dimensional plane navigation”, that is, the position of the carrier is solved in the plumb surface of the measured structure surface, and the trajectory of the carrier along the measured structure surface is finally obtained. According to the principle of trajectory method, its main error sources include reference error, distance measurement error and Angle measurement error. The reference error refers to the measurement error of the initial inclination Angle θ0, the distance measurement error refers to the measurement error of ΔLi, and the Angle measurement error refers to the measurement error of Δθi, which is mainly caused by the measurement error of the angular velocity of the fiber optic gyroscope. This paper does not consider the influence of reference error and distance measurement error on the deformation detection error, only the deformation detection error caused by the fiber optic gyroscope error is analyzed. 2 Analysis of deformation detection accuracy based on fiber optic gyroscope 2.1 Error modeling of fiber optic gyroscope in deformation detection applications Fiber optic gyro is a sensor for measuring angular velocity based on Sagnac effect. After the light emitted by the light source passes through the Y-waveguide, two beams of light rotating in opposite directions in the fiber ring are formed. When the carrier rotates relative to the inertial space, there is an optical path difference between the two beams of light, and the optical interference signal related to the rotational angular speed can be detected at the detector end, so as to measure the diagonal speed.The mathematical expression of the fiber optic gyro output signal is: F=Kw+B0+V. Where F is the gyro output, K is the scale factor, and ω is the gyroThe angular velocity input on the sensitive axis, B0 is the gyroscopic zero bias, υ is the integrated error term, including white noise and slowly varying components caused by various noises with long correlation time, υ can also be regarded as the error of zero bias.The sources of measurement error of fiber optic gyroscope include scale factor error and zero deviation error. At present, the scale factor error of the fiber optic gyroscope applied in engineering is 10-5~10-6. In the application of deformation detection, the angular velocity input is small, and the measurement error caused by the scale factor error is much smaller than that caused by the zero deviation error, which can be ignored. The DC component of the zero-bias error is characterized by the zero-bias repeatability Br, which is the standard deviation of the zero-bias value in multiple tests. The AC component is characterized by zero bias stability Bs, which is the standard deviation of the gyroscope output value from its mean in one test, and its value is related to the sampling time of the gyroscope. 2.2 Calculation of deformation error based on fiber optic gyroscope Taking the simple supported beam model as an example, the error of deformation detection is calculated, and the theoretical model of structural deformation is established. On this basis, the detection is setBased on the operating speed and sampling time of the system, the theoretical angular velocity of the fiber optic gyro can be obtained. Then the angular velocity measurement error of the fiber optic gyro can be simulated according to the zero deviation error model of the fiber optic gyro established above. 2.3 Example simulation calculation The simulation setting of running speed and sampling time adopts a range-varying mode, that is, the ΔLi passed by each sampling time is fixed, and the sampling time of the same line segment is changed by changing the running speed. For example, when the ΔLi is 1 mm, such as the running speed is 2 m/s, the sampling time is 0.5 ms. If the operating speed is 0.1 m/s, the sampling time is 10 ms. 3 Relationship between fiber optic gyroscope performance and deformation measurement error Firstly, the effect of zero-bias repeatability error is analyzed. When there is no zero bias stability error, the angular velocity measurement error caused by zero bias error is fixed, such as the faster the motion speed, the shorter the total measurement time, the smaller the impact of zero bias error, the smaller the deformation measurement error. When the running speed is fast, the zero bias stability error is the main factor causing the system measurement error. When the running speed is low, the zero bias repeatability error becomes the main source of the system measurement error.Using typical medium precision fiber optic gyro index, that is, zero bias stability is 0.5 °/h when sampling time is 1 s, Zero repeatability is 0.05 °/h. Compare the system measurement errors at the operating speed of 2 m/s, 1 m/s, 0.2 m/s, 0.1 m/s, 0.02 m/s, 0.01 m/s, 0.002 m/s and 0.001 m/s. When the operating speed is 2 m/s, The measurement error is 8.514μm (RMS), when the measurement speed is reduced to 0.2m /s, the measurement error is 34.089μm (RMS), when the measurement speed is reduced to 0.002m /s, the measurement error is 2246.222μm (RMS), as can be seen from the comparison results. The faster the running speed, the smaller the measuring error. Considering the convenience of engineering operation, the running speed of 2 m/s can achieve better than 10 μm measurement accuracy. 4 Summary Based on the simulation analysis of the engineering structure deformation measurement based on fiber optic gyro, the error model of fiber optic gyro is established, and the relationship between the deformation measurement error and the performance of fiber optic gyro is obtained by using the simple supported beam model as an example. The simulation results show that the faster the system runs, that is, the shorter the sampling time of the fiber optic gyroscope, the higher the deformation measurement accuracy of the system when the sampling number is unchanged and the distance detection accuracy is guaranteed. With the typical medium precision fiber optic gyro index and the running speed of 2 m/s, the deformation measurement accuracy of better than 10 μm can be achieved.Micro-Magic Inc GF-50 has a diameter of φ50*36.5mm and an accuracy of 0.1º/h. GF-60 precision 0.05º/h, belongs to the high tactical level of the fiber optic gyroscope, our company produced gyroscope with small size, light weight, low power consumption, fast start, simple operation, easy to use and other characteristics, widely used in INS, IMU, positioning system, north finding system, platform stability and other fields. If you are interested in our fiber optic gyro, please feel free to contact us. GF50 Single-Axis Medium Accuracy Military Standard Fiber Optic Gyroscope   GF60 Single Axis Fiber Gyro Low Power Fiber Optic Gyro Imu Angular Rate for Navigation  

Key Points Product: Fiber Optic Gyroscope (FOG) Key Features: Components: Based on optical fiber coils, utilizing the Sagnac effect for precise angular displacement measurements. Function: Offers high sensitivity and accuracy, ideal for determining orientation in moving objects. Applications: Widely used in military (e.g., missile guidance, tank navigation) and expanding into civilian sectors (e.g., automotive navigation, surveying). Data Fusion: Combines inertial measurements with advanced microelectronics for enhanced precision and stability. Conclusion: The fiber optic gyroscope is pivotal for high-precision navigation, with promising growth potential across diverse applications. Fiber optic gyroscope industry market With its unique advantages, fiber optic gyroscope has a broad development prospect in the field of precision physical quantity measurement. Therefore, exploring the influence of optical devices and physical environment on the performance of fiber optic gyros and suppressing the relative intensity noise have become the key technologies to realize the high precision fiber optic gyro. With the deepening of research, the integrated fiber gyroscope with high precision and miniaturization will be greatly developed and applied. Fiber optic gyroscope is one of the mainstream devices in the field of inertia technology at present. With the improvement of technical level, the application scale of fiber optic gyro will continue to expand. As the core component of fiber optic gyros, the market demand will also grow. At present, China’s high-end optical fiber ring still needs to be imported, and under the general trend of domestic substitution, the core competitiveness of China’s optical fiber ring enterprises and independent research and development capabilities still need to be further enhanced. At present, the optical fiber ring is mainly used in the military field, but with the expansion of the application of optical fiber gyroscope to the civilian field, the application proportion of optical fiber ring in the civilian field will be further improved. According to the "2022-2027 China Fiber Optic Gyroscope industry Market Survey and Investment Advice Analysis Report" : The fiber optic gyroscope is a sensitive element based on the optical fiber coil, and the light emitted by the laser diode propagates along the optical fiber in two directions. The difference of light propagation path determines the angular displacement of the sensitive element. Modern fiber optic gyro is an instrument that can accurately determine the orientation of moving objects. It is an inertial navigation instrument widely used in modern aviation, navigation, aerospace and national defense industries. Its development is of great strategic significance to a country’s industry, national defense and other high-tech development.Fiber optic gyro is a new all-solid-state fiber optic sensor based on Sagnac effect. Fiber optic gyro can be divided into interferometric fiber optic gyros (I-FOG), resonant fiber optic gyro (R-FOG) and stimulated Brillouin scattering fiber optic gyro (B-FOG) according to its working mode. According to its accuracy, fiber optic gyro can be divided into: low-end tactical level, high-end tactical level, navigation level and precision level. Fiber optic gyroscopes can be divided into military and civilian according to their openness. At present, most fiber optic gyros are used in military aspects: fighter and missile attitude, tank navigation, submarine heading measurement, infantry fighting vehicles and other fields. Civil use is mainly automobile and aircraft navigation, bridge surveying, oil drilling and other fields.Depending on the accuracy of the fiber optic gyroscope, its applications range from strategic weapons and equipment to commercial grade civilian fields. Medium and high-precision fiber optic gyroscopes are mainly used in high-end weapons and equipment fields such as aerospace, while low-cost, low-precision fiber optic gyroscopes are mainly used in oil exploration, agricultural aircraft attitude control, robots and many other civilian fields with low precision requirements. With the development of advanced microelectronics and optoelectronics technologies, such as photoelectric integration and the development of special fiber optics for fiber optic gyros, the miniaturization and low-cost of fiber optic gyros have been accelerated. Summary Micro-Magic Inc’s fiber optic gyro is mainly a medium precision tactical fiber optic gyro, compared with other manufacturers, low cost, long service life, the price is very dominant, and the application field is also very wide, including two very hot selling GF50, GF-60, you can click the details page for more technical data. GF50 Single-Axis Medium Accuracy Military Standard Fiber Optic Gyroscope   GF60 Single Axis Fiber Gyro Low Power Fiber Optic Gyro Imu Angular Rate for Navigation  

Key Points   Product: Fiber Optic Gyroscope GF70ZK Key Features: Components: Employs fiber optic gyroscopes for high precision inertial measurements. Function: Provides rapid start-up and reliable navigation data for various applications. Applications: Suitable for inertial navigation systems, platform stability, and positioning systems in aerospace and autonomous vehicles. Performance: Zero bias stability between 0.01 and 0.02, tailored for accuracy and measurement range needs. Conclusion: The GF70ZK combines compact size and low power consumption, making it a versatile choice for demanding navigation tasks across multiple industries. 1. What is inertial navigation To understand what inertial navigation is, we first need to break the phrase into two parts, that is, navigation + inertia.Navigation, in simple terms, solves the problem of getting from one place to another, indicating the direction, typically the compass.Inertia, originally derived from Newtonian mechanics, refers to the property of an object that maintains its state of motion. It has the function of recording the motion state information of the object.A simple example is used to illustrate inertial navigation. A child and a friend play a game at the entrance of a room covered with tiles, and walk on the tiles to the other side according to certain rules. One forward, three left, five front, two right… Each of his steps is the length of a floor tile, and people outside the room can get his complete motion trajectory by drawing the corresponding length and route on the paper. He doesn’t need to see the room to know the child’s position, speed, etc.The basic principle of inertial navigation and some other types of navigation is pretty much like this: know your initial position, initial orientation (attitude), the direction and direction of movement at each moment, and push forward a little bit. Add these together (corresponding to the mathematical integration operation), and you can just get your orientation, position and other information.So how to get the current orientation (attitude) and position information of the moving object? You need to use a lot of sensors, in inertial navigation is the use of inertial instruments: accelerometer + gyroscope.Inertial navigation uses gyroscope and accelerometer to measure the angular velocity and acceleration of the carrier in the inertial reference frame, and integrates and calculates the time to obtain the velocity and relative position, and transforms it into the navigation coordinate system, so that the carrier’s current position can be obtained by combining the initial position information.Inertial navigation is an internal closed loop navigation system, and there is no external data input to correct the error during the carrier movement. Therefore, a single inertial navigation system can only be used for short periods of navigation. For the system running for a long time, it is necessary to periodically correct the internal accumulated error by means of satellite navigation. 2. Gyroscopes in inertial navigation Inertial navigation technology is widely used in aerospace, navigation satellite, UAV and other fields because of its high concealment and complete autonomous ability to obtain motion information. Especially in the fields of micro-drones and autonomous driving, inertial navigation technology can provide accurate direction and speed information, and can play an irreplaceable role in complex conditions or when other external auxiliary navigation signals fail to play the advantages of autonomous navigation in the environment to achieve reliable attitude and position measurement. As an important component in inertial navigation system, fiber optic gyro plays a decisive role in its navigation ability. At present, there are mainly fiber optic gyroscopes and MEMS gyroscopes on the market. Although the precision of the fiber optic gyroscope is high, its entire system is composed of couplers,modulator, optical fiber ring and other discrete components, resulting in large volume, high cost, in the micro UAV, unmanned and other fields can not meet the requirements for its miniaturization and low cost, the application is greatly limited. Although MEMS gyro can achieve miniaturization, its accuracy is low. In addition, it has moving parts, poor resistance to shock and vibration, and is difficult to apply in harsh environments. 3 Summary Micro-Magic Inc’s fiber optic gyroscope GF70ZK is specially designed according to the concept of traditional fiber optic gyroscopes, with a small size of 70*70*32mm; Light weight, less than or equal to 250g; Low power consumption, less than or equal to 4W; Start fast, start time is only 5s; This fiber optic gyroscope easy to operate and easy to use, and is widely used in INS, IMU, positioning system, north finding system, platform stability and other fields.The zero bias stability of our GF80 is between 0.01 and 0.02. The biggest difference between these two fiber optic gyroscope is that the measurement range is different, of course, Our fiber optic gyroscope can be used in inertial navigation, you can make a detailed choice according to the accuracy value and measurement range, you are welcome to consult us at any time and get more technical data. GF70ZK Fibre Optic Gyroscope Sensors North Finder Navigation Inertial Navigation Attitude/Azimuth Reference System   G-F80 Miniature Fiber Optic Gyro Sensors 80mm Compact Size  

Key Points Product: Navigation-Grade MEMS Gyroscope Key Features: Components: MEMS gyroscope for precise angular velocity measurement. Function: Provides high-accuracy navigation data with low drift, suitable for long-term and stable navigation. Applications: Ideal for aerospace, tactical missile guidance, marine navigation, and industrial robotics. Performance: Features low bias instability and random drift, offering reliable performance over time. Comparison: Different models (MG-101, MG-401, MG-501) cater to varying accuracy needs, with the MG-101 providing the highest precision. MEMS gyroscope is a kind of inertial sensor for measuring angular velocity or angular displacement. It has a wide application prospect in oil logging, weapon guidance, aerospace, mining, surveying and mapping, industrial robot and consumer electronics. Due to the different accuracy requirements in various fields, MEMS gyroscopes are divided into three levels in the market: navigation level, tactical level and consumer level. This paper will introduce the navigation MEMS gyroscope in detail and compare their parameters. The following will be elaborated from the technical indicators of MEMS gyro, the drift analysis of gyro and the comparison of three navigation-grade MEMS gyro. Technical specifications of MEMS gyroscope The ideal MEMS gyroscope is that the output of its sensitive axis is proportional to the input angular parameters (Angle, angular rate) of the corresponding axis of the carrier under any conditions, and is not sensitive to the angular parameters of its cross axis, nor is it sensitive to any axial non-angular parameters (such as vibration acceleration and linear acceleration). The main technical indicators of MEMS gyroscope are shown in Table 1. Technical indicator Unit Meaning Measuring range (°)/s Effectively sensitive to the range of input angular velocity Zero bias (°)/h The output of a gyroscope when the input rate in the gyroscope is zero. Because the output is different, the equivalent input rate is usually used to represent the same type of product, and the smaller the zero bias, the better; Different models of products, not the smaller the zero bias, the better. Bias repeatability (°)/h(1σ) Under the same conditions and at specified intervals (successive, daily, every other day…) The degree of agreement between the partial values of repeated measurements. Expressed as the standard deviation of each measured offset. Smaller is better for all gyroscopes (evaluate how easy it is to compensate for zero) Zero drift (°)/s The rate of time change of the deviation of the gyroscope output from the ideal output. It contains both stochastic and systematic components and is expressed in terms of the corresponding input angular displacement relative to inertial space in unit time. Scale factor V/(°)/s、mA/(°)/s The ratio of the change in the output to the change in the input to be measured. Bandwidth Hz In the frequency characteristic test of gyroscope, it is stipulated that the frequency range corresponding to the amplitude of the measured amplitude is reduced by 3dB, and the precision of the gyroscope can be improved by sacrificing the bandwidth of the gyroscope. Table 1 Main technical indexes of MEMS gyroscope Drift analysis of gyroscope If there is interference torque in the gyroscope, the rotor shaft will deviate from the original stable reference azimuth and form an error. The deviation Angle of rotor axis relative to inertial space azimuth (or reference azimuth) in unit time is called gyro drift rate. The main index to measure the accuracy of gyroscope is the drift rate. Gyroscopic drift is divided into two categories: one is systematic, the law is known, it causes regular drift, so it can be compensated by computer; The other kind is caused by random factors, which causes random drift. The systematic drift rate is expressed by the angular displacement per unit time, and the random drift rate is expressed by the root mean square value of the angular displacement per unit time or the standard deviation. The approximate range of random drift rates of various types of gyroscopes can be reached at present is shown in Table 2. Gyroscope type Random drift rate/(°)·h-1 Ball bearing gyroscope 10-1 Rotary bearing gyroscope 1-0.1 Liquid float gyroscope 0.01-0.001 Air float gyroscope 0.01-0.001 Dynamically tuned gyroscope 0.01-0.001 Electrostatic gyroscope 0.01-0.0001 Hemispherical resonant gyroscope 0.1-0.01 Ring laser gyroscope 0.01-0.001 Fiber optic gyroscope 1-0.1 Table 2 Random drift rates of various types of gyroscopes   The approximate range of random drift rate of gyro required by various applications is shown in Table 3. The typical index of positioning accuracy of inertial navigation system is 1n mile/h(1n mile=1852m), which requires the gyroscope random drift rate should reach 0.01(°)/h, so the gyroscope with random drift rate of 0.01(°)/h is usually called inertial navigation gyroscope. Application Requirements for random drift rate of gyro/(°)·h-1 Rate gyroscope in flight control system 150-10 Vertical gyroscope in flight control system 30-10 Directional gyroscope in the flight control system 10-1 Tactical missile inertial guidance system 1-0.1 Marine gyro compass, strapdown heading attitude system artillery lateral position, ground vehicle inertial navigation system 0.1-0.01 Inertial navigation systems for aircraft and ships 0.01-0.001 Strategic missile, cruise missile inertial guidance system 0.01-0.0005 Table 3 Requirements for random drift rate of gyro in various applications   Comparison of three navigation-grade MEMS gyroscopes Micro-Magic Inc’s MG series is a navigation-grade MEMS gyroscope with a high level of accuracy to meet the needs of various fields. The following table compares range, bias instability, angular random walk, bias stability, scale factor, bandwidth, and noise. 　 MG-101 MG-401 MG-501 Dynamic Range (deg/s) ±100 ±400 ±500 Bias instability(deg/hr) 0.1 0.5 2 Angular Random Walk(°/√h) 0.005 0.025~0.05 0.125-0.1 Bias stability(1σ 10s)(deg/hr) 0.1 0.5 2~5 Table 4 Parameter comparison table of three navigation-grade MEMS gyroscopes I hope that through this article, you can understand the technical indicators of navigation-grade MEMS gyroscope and the comparative relationship between them. If you are interested in more knowledge about MEMS gyro, please discuss with us.   MG502 MEMS Gyroscope MG502